"He said it did not fall within the anti-torture act. I'm not a lawyer. But you've got to trust the judgement of people around you, and I do," Mr Bush said.

"I will tell you this: using those techniques saved lives. My job was to protect America. And I did."

Human rights groups have hit out at Mr Bush's defence of the interrogation technique. Steve Ballinger, from Liberty, said Mr Bush was wrong to say waterboarding as justified "because torture is illegal under international law".

"It is completely banned in all circumstances by the United Nations convention against torture and the US is a state party to that so it should not be doing it," he added.

Mr Lauer asked Mr Bush of the "sickening feeling" he describes in Decision Points every time he thinks about the failure to find weapons of mass destruction in Iraq after the 2003 invasion that toppled Saddam Hussein.

"Was there ever any consideration of apologising to the American people?" Mr Lauer asked.

"I mean, apologising would basically say the decision was a wrong decision," Mr Bush replied. "And I don't believe it was the wrong decision."

He said it might be some time before history is able to judge his presidency.

"I hope I'm judged a success. But I'm gonna be dead, Matt, when they finally figure it out," he said.

Economic woes

In his memoir, Mr Bush admits the economic woes he left to his successor, Barack Obama, were "one ugly way to end a presidency".

Decision Points: Bush's revelations

Defends the use of waterboarding, saying the interrogation technique "saved lives"

Fell out with Vice-President Cheney over the case of "Scooter" Libby, convicted for leaking the identity of a CIA spy

In 2003, offered the then UK Prime Minister Tony Blair a chance to opt out of sending British troops to Iraq

Says the bank bailout in 2008 sent a signal that the US financial system would not be allowed to fail

Admits his administration's response to Hurricane Katrina in New Orleans in 2005 "cast a cloud" over his second term